1. Field of the Invention
The invention concerns a combination of a self-propelled harvester and a transport vehicle set up to receive crops from the harvester, which has at least one driven and at least one steered axle, wherein the transport vehicle has an electronic control unit which is set up to control the driven and steered axle of the transport vehicle, and the control unit is connected with a receiving unit that is set up to receive position data for the harvester, so that the control unit can be operated to control the transport vehicle to receive crops from the harvester automatically, relative to a position of the harvester.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
In the mid-1950s, one-axle vehicles in agriculture were replaced by driving-axle trailers, since tractors with low but sufficient power did not have sufficient mass to pull the trailers, which were twice as heavy under adverse weather conditions. The driving-axle trailer was coupled to the tractor with a mechanical towing bar and driven by means of the tractor's power take-off shaft. The traction weight of the transport unit could, in this way, be increased by the mass of the driving-axle trailer plus the load, and thus be distributed on the wheels so that each wheel also drove and braked the load which it carried. Since suitable control electronics were still lacking so as to adapt the rotational speed of the tractor wheels and driving-axle trailer wheels to different curve radii, it happened under certain conditions that the driving-axle trailer would topple the tractor, which led to deadly accidents. The production and sale of driving-axle trailers was therefore discontinued. Present-day electronics permit the functionality described above to be constituted safely.
In the VDI [Association of German Engineers] Report 1356 “Farm Technology 1997,” Tapazdi summarized results of his dissertation “Possibilities in improving the wheel-ground contact” as follows:
%Schlupf {circle around (1)}BodenBoden%Lfd. {circle around (2)}Fahrzeugantrieb {circle around (3)}normal {circle around (4)}nass {circle around (5)}schwer/nass {circle around (6)}1Hinterradantrieb {circle around (7)}22406021 + Vorderrad {circle around (8)}20285532 + Triebachser {circle around (9)}18204043 + Reifendruck {circle around (10)}141635Key:{circle around (1)} Slippage{circle around (2)} Consecutive{circle around (3)} Vehicle drive{circle around (4)} Ground normal{circle around (5)} Ground wet{circle around (6)} Heavy/wet{circle around (7)} Rear wheel drive{circle around (8)} 1 + Front wheel{circle around (9)} 2 + Driving axle{circle around (10)} 3 + Tire pressure
The slippage values refer to the rear wheel of the tractor, wherein a slippage of 20% represents a good value in agriculture for normal ground. From the table one can see that this value is established after switching on the front wheel driving axle. Switching on the driving-axle trailer does not bring any substantial advantages under the described conditions.
On wet ground, however, a slippage of 20% can be maintained only after switching on the drive of the driving-axle trailer. On wet, heavy ground, however, this measure is not sufficient to ensure a satisfactory mobility and traction. However, activation of the tire pressure regulation unit on all wheels can prevent the transport vehicles from getting stuck.
If one considers the size and the weight of the transport trailers displayed at the Agritechnica Fair, Hannover 2001, and the self-propelled harvesters and the increased throughputs of the machines due to the greater work widths and higher speeds, then the demand must be made to lower the stress on the ground by using lightweight materials and improved machine designs. With regard to machine designs, the following rough calculations can be made. If one assumes a throughput of a field chaff-cutter of 150 t/h, then 8.3 transport vehicles of the unit “tractor plus 20 t tandem-trailer (not driven)” are needed, without addressing transport distance factors.
If one uses a tandem-driving-axle trailer, which can also pull a 30-ton three-axle trailer, then the transport needs can be managed by 3.3 transport units. That means a savings of 5 tractors, which must offset the costs for the single-wheel drives of the driving-axle trailers.
If, with a knowledge of experiments with “driver assistance systems,” one attacks the problem in a very logical manner and switches to tridem-driving-axle trailers, then there can be an economizing of 8.3 tractors, wherein the chaff material of 2.8 rigs can be handled with two tridem-driving-axle trailers.
In June 1999, Daimler-Chrysler presented, on the Autobahn A 81, prototypes of two commercial vehicles with an “electronic towing bar.” The two vehicles were electronically coupled with one another so that the leading vehicle was steered, accelerated, and decelerated by a driver, as usual, while the following vehicle, without a driver, followed the lead vehicle with a “virtual towing bar,” as it were, at a short distance and a matched speed.
Driver assistance systems of this type differ from the servo systems in that they are equipped with additional electronics and have intelligence, relieving the driver of driving decisions and steering work in critical situations.
That can be explained with the example of ABS brakes. ABS intervenes if the driver overbrakes the vehicle so that the wheels tend to lock. With ABS, however, locking of the wheels can be avoided without driver involvement, so that the control of the vehicle on the road is not lost and it can be safely braked. Future vehicles are no longer conceivable without driver assistance of this type and without mechatronics.
DE 197 05 842 A describes a harvesting method in which harvesters are remote-controlled from a control site. However, the harvester can also be conducted on its path by a navigation system, for example, GPS, or by systems for the row recognition of harvest crops, wherein they are supervised by the control site. If the grain hopper of a combine is full, a harvest vehicle is sent from the control site to the combine to empty the grain hopper. The grain hopper can be controlled by remote control or by operators. A self-activated or automatic control of the harvest vehicle cannot be found in this publication. It can thus be regarded as disadvantageous that an operator must be provided for the remote control or operation of the harvest vehicle.
WO 00/35265 A describes an electronically supported operating method for a combine and a transport vehicle. The combine is provided with means to detect how full its grain hopper is. With the aid of the degree of grain hopper fullness, a map of the field and a position determination device provided with a satellite receiving unit, a determination is made as to when and at what location a transfer of the grain to the transport vehicle should take place. The transport vehicle equipped with a position determination device is then instructed, through a correspondingly informed driver or automatically, to go at the expected time to the expected location where the transfer operation is to take place. Parallel travel of the combine and the transport vehicle while emptying of the tank is not disclosed. The transport vehicle is a conventional tractor that is equipped with a driver's cab and corresponding operating devices.
DE 100 57 374 A, published after the priority date of the patent under consideration, describes a combination of a transport vehicle and a harvester. The transport vehicle is provided with an operator position from which the harvester can be remotely controlled. The harvester can also be moved along rows of crops. There is the possibility of synchronizing the speeds and steering of the two vehicles so as to facilitate the transfer of the crop from the harvester to the crop transport vehicle.
A similar procedure is described in DE 100 64 862 A, which was also published after the priority date of the patent under consideration. The harvester transmits information on its position, determined by a satellite receiving system, to the transport vehicle, which is provided with a display for the driver or is driver automatically, so that it drives to a desired position next to the self-propelled harvester and receives the crop. The transport vehicle is provided with a driver operating position.
The problem of the invention under consideration is to make available an unmanned and autonomously driven transport vehicle which is suitable for receiving the crop from a harvester while traveling.